1. Field of the Invention
The present invention relates to a floating-gate semiconductor memory device.
2. Description of the Related Art
In recent years, semiconductor memory devices such as flash memories which store data by accumulation of electric charge in floating gates (hereinafter, referred to as FG memory devices) have been used for many electronic devices, home appliances, and the like. FG memory devices are highly integrated, and in accordance with that, cost per bit is reduced.
Although silicon has been often used for floating gates conventionally (for example, see Patent Document 1), in recent years, attempts to use materials other than silicon have been reported (for example, see Non-Patent Document 1). In addition, use of semiconductor particles instead of floating gates has been proposed (for example, see Patent Documents 2 and 3).